code: def mock_candidate_number():
      os.environ["CANDIDATE_AGENT_NUMBER"] = "2"
      yield
      os.environ.pop("CANDIDATE_AGENT_NUMBER", None)
  
imports: from pathlib import Path
  import tempfile
  import time
  import os
  from ray.dashboard.modules.job.pydantic_models import JobType
  import requests
  import pytest
  import psutil
  import sys
  from typing import Dict, Optional, Tuple
  from unittest.mock import Mock, patch
  from ray._private.ray_constants import DEFAULT_DASHBOARD_AGENT_LISTEN_PORT
  from ray._private.test_utils import format_web_url, wait_for_condition, wait_until_server_available
  from ray.dashboard.modules.dashboard_sdk import ClusterInfo, DEFAULT_DASHBOARD_ADDRESS, parse_cluster_info
  from ray.dashboard.modules.job.sdk import JobSubmissionClient, JobStatus
  from ray.dashboard.tests.conftest import *
  from ray.dashboard.consts import RAY_JOB_ALLOW_DRIVER_ON_WORKER_NODES_ENV_VAR
  from ray.tests.conftest import _ray_start
  import ray
  import ray.experimental.internal_kv
  from ray.util.state import list_nodes
label_desc: Use image node_id 6 for calling a global function with example usage: mock_candidate_number() without return types